1
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Baserga F, Storm J, Schlesinger R, Heberle J, Stripp ST. The catalytic reaction of cytochrome c oxidase probed by in situ gas titrations and FTIR difference spectroscopy. Biochim Biophys Acta Bioenerg 2023; 1864:149000. [PMID: 37516233 DOI: 10.1016/j.bbabio.2023.149000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 06/22/2023] [Accepted: 07/24/2023] [Indexed: 07/31/2023]
Abstract
Cytochrome c oxidase (CcO) is a transmembrane heme‑copper metalloenzyme that catalyzes the reduction of O2 to H2O at the reducing end of the respiratory electron transport chain. To understand this reaction, we followed the conversion of CcO from Rhodobacter sphaeroides between several active-ready and carbon monoxide-inhibited states via attenuated total reflection Fourier-transform infrared (ATR FTIR) difference spectroscopy. Utilizing a novel gas titration setup, we prepared the mixed-valence, CO-inhibited R2CO state as well as the fully-reduced R4 and R4CO states and induced the "active ready" oxidized state OH. These experiments are performed in the dark yielding FTIR difference spectra exclusively triggered by exposure to O2, the natural substrate of CcO. Our data demonstrate that the presence of CO at heme a3 does not impair the catalytic oxidation of CcO when the cycle starts from the fully-reduced states. Interestingly, when starting from the R2CO state, the release of the CO ligand upon purging with inert gas yield a product that is indistinguishable from photolysis-induced states. The observed changes at heme a3 in the catalytic binuclear center (BNC) result from the loss of CO and are unrelated to electronic excitation upon illumination. Based on our experiments, we re-evaluate the assignment of marker bands that appear in time-resolved photolysis and perfusion-induced experiments on CcO.
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Affiliation(s)
- Federico Baserga
- Freie Universität Berlin, Experimental Molecular Biophysics, Arnimallee 14, D-14195 Berlin, Germany
| | - Julian Storm
- Freie Universität Berlin, Genetic Biophysics, Arnimallee 14, D-14195 Berlin, Germany
| | - Ramona Schlesinger
- Freie Universität Berlin, Genetic Biophysics, Arnimallee 14, D-14195 Berlin, Germany
| | - Joachim Heberle
- Freie Universität Berlin, Experimental Molecular Biophysics, Arnimallee 14, D-14195 Berlin, Germany
| | - Sven T Stripp
- Freie Universität Berlin, Experimental Molecular Biophysics, Arnimallee 14, D-14195 Berlin, Germany; Technische Universität Berlin, Division of Physical Chemistry, Strasse des 17. Juni 115, D-10623 Berlin, Germany.
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2
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Katsyv A, Kumar A, Saura P, Pöverlein MC, Freibert SA, T Stripp S, Jain S, Gamiz-Hernandez AP, Kaila VRI, Müller V, Schuller JM. Molecular Basis of the Electron Bifurcation Mechanism in the [FeFe]-Hydrogenase Complex HydABC. J Am Chem Soc 2023; 145:5696-5709. [PMID: 36811855 PMCID: PMC10021017 DOI: 10.1021/jacs.2c11683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Electron bifurcation is a fundamental energy coupling mechanism widespread in microorganisms that thrive under anoxic conditions. These organisms employ hydrogen to reduce CO2, but the molecular mechanisms have remained enigmatic. The key enzyme responsible for powering these thermodynamically challenging reactions is the electron-bifurcating [FeFe]-hydrogenase HydABC that reduces low-potential ferredoxins (Fd) by oxidizing hydrogen gas (H2). By combining single-particle cryo-electron microscopy (cryoEM) under catalytic turnover conditions with site-directed mutagenesis experiments, functional studies, infrared spectroscopy, and molecular simulations, we show that HydABC from the acetogenic bacteria Acetobacterium woodii and Thermoanaerobacter kivui employ a single flavin mononucleotide (FMN) cofactor to establish electron transfer pathways to the NAD(P)+ and Fd reduction sites by a mechanism that is fundamentally different from classical flavin-based electron bifurcation enzymes. By modulation of the NAD(P)+ binding affinity via reduction of a nearby iron-sulfur cluster, HydABC switches between the exergonic NAD(P)+ reduction and endergonic Fd reduction modes. Our combined findings suggest that the conformational dynamics establish a redox-driven kinetic gate that prevents the backflow of the electrons from the Fd reduction branch toward the FMN site, providing a basis for understanding general mechanistic principles of electron-bifurcating hydrogenases.
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Affiliation(s)
- Alexander Katsyv
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main 60438, Germany
| | - Anuj Kumar
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main 60438, Germany.,SYNMIKRO Research Center and Department of Chemistry, Philipps-University of Marburg, Marburg 35032, Germany
| | - Patricia Saura
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
| | - Maximilian C Pöverlein
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
| | - Sven A Freibert
- Institut für Zytobiologie im Zentrum SYNMIKRO, Philipps-University of Marburg, Marburg 35032, Germany.,Core Facility "Protein Biochemistry and Spectroscopy", Marburg 35032, Germany
| | - Sven T Stripp
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Berlin 14195, Germany
| | - Surbhi Jain
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main 60438, Germany
| | - Ana P Gamiz-Hernandez
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
| | - Ville R I Kaila
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
| | - Volker Müller
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main 60438, Germany
| | - Jan M Schuller
- SYNMIKRO Research Center and Department of Chemistry, Philipps-University of Marburg, Marburg 35032, Germany
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3
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Sidabras JW, Stripp ST. A personal account on 25 years of scientific literature on [FeFe]-hydrogenase. J Biol Inorg Chem 2023; 28:355-378. [PMID: 36856864 DOI: 10.1007/s00775-023-01992-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 01/25/2023] [Indexed: 03/02/2023]
Abstract
[FeFe]-hydrogenases are gas-processing metalloenzymes that catalyze H2 oxidation and proton reduction (H2 release) in microorganisms. Their high turnover frequencies and lack of electrical overpotential in the hydrogen conversion reaction has inspired generations of biologists, chemists, and physicists to explore the inner workings of [FeFe]-hydrogenase. Here, we revisit 25 years of scientific literature on [FeFe]-hydrogenase and propose a personal account on 'must-read' research papers and review article that will allow interested scientists to follow the recent discussions on catalytic mechanism, O2 sensitivity, and the in vivo synthesis of the active site cofactor with its biologically uncommon ligands carbon monoxide and cyanide. Focused on-but not restricted to-structural biology and molecular biophysics, we highlight future directions that may inspire young investigators to pursue a career in the exciting and competitive field of [FeFe]-hydrogenase research.
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Affiliation(s)
- Jason W Sidabras
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI, USA, 53226.
| | - Sven T Stripp
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany.
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4
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Grinter R, Kropp A, Venugopal H, Senger M, Badley J, Cabotaje PR, Jia R, Duan Z, Huang P, Stripp ST, Barlow CK, Belousoff M, Shafaat HS, Cook GM, Schittenhelm RB, Vincent KA, Khalid S, Berggren G, Greening C. Structural basis for bacterial energy extraction from atmospheric hydrogen. Nature 2023; 615:541-547. [PMID: 36890228 PMCID: PMC10017518 DOI: 10.1038/s41586-023-05781-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 02/02/2023] [Indexed: 03/10/2023]
Abstract
Diverse aerobic bacteria use atmospheric H2 as an energy source for growth and survival1. This globally significant process regulates the composition of the atmosphere, enhances soil biodiversity and drives primary production in extreme environments2,3. Atmospheric H2 oxidation is attributed to uncharacterized members of the [NiFe] hydrogenase superfamily4,5. However, it remains unresolved how these enzymes overcome the extraordinary catalytic challenge of oxidizing picomolar levels of H2 amid ambient levels of the catalytic poison O2 and how the derived electrons are transferred to the respiratory chain1. Here we determined the cryo-electron microscopy structure of the Mycobacterium smegmatis hydrogenase Huc and investigated its mechanism. Huc is a highly efficient oxygen-insensitive enzyme that couples oxidation of atmospheric H2 to the hydrogenation of the respiratory electron carrier menaquinone. Huc uses narrow hydrophobic gas channels to selectively bind atmospheric H2 at the expense of O2, and 3 [3Fe-4S] clusters modulate the properties of the enzyme so that atmospheric H2 oxidation is energetically feasible. The Huc catalytic subunits form an octameric 833 kDa complex around a membrane-associated stalk, which transports and reduces menaquinone 94 Å from the membrane. These findings provide a mechanistic basis for the biogeochemically and ecologically important process of atmospheric H2 oxidation, uncover a mode of energy coupling dependent on long-range quinone transport, and pave the way for the development of catalysts that oxidize H2 in ambient air.
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Affiliation(s)
- Rhys Grinter
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
| | - Ashleigh Kropp
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Hari Venugopal
- Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, Victoria, Australia
| | - Moritz Senger
- Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Jack Badley
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Princess R Cabotaje
- Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Ruyu Jia
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Zehui Duan
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford, UK
| | - Ping Huang
- Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Sven T Stripp
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Christopher K Barlow
- Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Monash Proteomics and Metabolomics Facility, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Matthew Belousoff
- Centre for Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Hannah S Shafaat
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Gregory M Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Ralf B Schittenhelm
- Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Monash Proteomics and Metabolomics Facility, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Kylie A Vincent
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford, UK
| | - Syma Khalid
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Gustav Berggren
- Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
- Securing Antarctica's Environmental Future, Monash University, Clayton, Victoria, Australia.
- Centre to Impact AMR, Monash University, Clayton, Victoria, Australia.
- ARC Research Hub for Carbon Utilisation and Recycling, Monash University, Clayton, Victoria, Australia.
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5
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Duan J, Hemschemeier A, Burr DJ, Stripp ST, Hofmann E, Happe T. Cyanide Binding to [FeFe]-Hydrogenase Stabilizes the Alternative Configuration of the Proton Transfer Pathway. Angew Chem Int Ed Engl 2023; 62:e202216903. [PMID: 36464641 PMCID: PMC10107461 DOI: 10.1002/anie.202216903] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/02/2022] [Accepted: 12/02/2022] [Indexed: 12/12/2022]
Abstract
Hydrogenases are H2 converting enzymes that harbor catalytic cofactors in which iron (Fe) ions are coordinated by biologically unusual carbon monoxide (CO) and cyanide (CN- ) ligands. Extrinsic CO and CN- , however, inhibit hydrogenases. The mechanism by which CN- binds to [FeFe]-hydrogenases is not known. Here, we obtained crystal structures of the CN- -treated [FeFe]-hydrogenase CpI from Clostridium pasteurianum. The high resolution of 1.39 Å allowed us to distinguish intrinsic CN- and CO ligands and to show that extrinsic CN- binds to the open coordination site of the cofactor where CO is known to bind. In contrast to other inhibitors, CN- treated crystals show conformational changes of conserved residues within the proton transfer pathway which could allow a direct proton transfer between E279 and S319. This configuration has been proposed to be vital for efficient proton transfer, but has never been observed structurally.
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Affiliation(s)
- Jifu Duan
- Department of Plant Biochemistry, Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - Anja Hemschemeier
- Department of Plant Biochemistry, Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - David J Burr
- Department of Physics, Experimental Biophysics and Space Sciences, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Sven T Stripp
- Department of Biophysics, Experimental Molecular Biophysics, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Eckhard Hofmann
- Department of Biophysics, Faculty of Biology and Biotechnology, Protein Crystallography, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - Thomas Happe
- Department of Plant Biochemistry, Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
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6
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Duan J, Hemschemeier A, Burr DJ, Stripp ST, Hofmann E, Happe T. Cyanide Binding to [FeFe]‐Hydrogenase Stabilizes the Alternative Configuration of the Proton Transfer Pathway. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202216903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Jifu Duan
- Ruhr-Universität Bochum: Ruhr-Universitat Bochum Plant Biochemistry Universitätsstrasse 150 44801 Bochum GERMANY
| | - Anja Hemschemeier
- Ruhr-Universität Bochum: Ruhr-Universitat Bochum Department of Plant Biochemistry GERMANY
| | - David J. Burr
- Free University of Berlin: Freie Universitat Berlin Department of Biophysics GERMANY
| | - Sven T. Stripp
- Free University of Berlin: Freie Universitat Berlin Department of Biophysics GERMANY
| | - Eckhard Hofmann
- Ruhr University Bochum: Ruhr-Universitat Bochum Department of Biophysics GERMANY
| | - Thomas Happe
- Ruhr University Bochum: Ruhr-Universitat Bochum Department of Plant Biochemistry GERMANY
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7
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Soboh B, Adrian L, Stripp ST. An in vitro reconstitution system to monitor iron transfer to the active site during the maturation of [NiFe]-hydrogenase. J Biol Chem 2022; 298:102291. [PMID: 35868564 PMCID: PMC9418501 DOI: 10.1016/j.jbc.2022.102291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 07/13/2022] [Accepted: 07/16/2022] [Indexed: 11/29/2022] Open
Abstract
[NiFe]-hydrogenases comprise a small and a large subunit. The latter harbors the biologically unique [NiFe](CN)2CO active site cofactor. The maturation process includes the assembly of the [Fe](CN)2CO cofactor precursor, nickel binding, endoproteolytic cleavage of the large subunit, and dimerization with the small subunit to yield active enzyme. The biosynthesis of the [Fe](CN)2CO moiety of [NiFe]-Hydrogenase 1 (Hyd-1) and Hyd-2 occurs on the scaffold complex HybG-HypD (GD), whereas the HypC-HypD complex (CD) is specific for the assembly of Hyd-3. The metabolic source and the route for delivering iron to the active site remain unclear. To investigate the maturation process of O2-tolerant Hyd-1 from Escherichia coli, we developed an enzymatic in vitro reconstitution system that allows for the synthesis of Hyd-1 using only purified components. Together with this in vitro reconstitution system, we employed biochemical analyses, infrared spectroscopy (ATR FTIR), mass spectrometry, and microscale thermophoresis (MST) to monitor the iron transfer during the maturation process and to understand how the [Fe](CN)2CO cofactor precursor is ultimately incorporated into the large subunit. We demonstrate the direct transfer of iron from 57Fe-labeled GD complex to the large subunit of Hyd-1. Our data reveal that the GD complex exclusively interacts with the large subunit of Hyd-1 and Hyd-2 but not with the large subunit of Hyd-3. Furthermore, we show that the presence of iron in the active site is a prerequisite for nickel insertion. Taken together, these findings reveal how the [Fe](CN)2CO cofactor precursor is transferred and incorporated into the active site of [NiFe]-hydrogenase.
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Affiliation(s)
- Basem Soboh
- Genetic Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany.
| | - Lorenz Adrian
- Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany; Chair of Geobiotechnology, Technische Universität Berlin, Ackerstraße 76, 13355 Berlin, Germany
| | - Sven T Stripp
- Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
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Stripp ST, Duffus BR, Fourmond V, Léger C, Leimkühler S, Hirota S, Hu Y, Jasniewski A, Ogata H, Ribbe MW. Second and Outer Coordination Sphere Effects in Nitrogenase, Hydrogenase, Formate Dehydrogenase, and CO Dehydrogenase. Chem Rev 2022; 122:11900-11973. [PMID: 35849738 PMCID: PMC9549741 DOI: 10.1021/acs.chemrev.1c00914] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Gases like H2, N2, CO2, and CO are increasingly recognized as critical feedstock in "green" energy conversion and as sources of nitrogen and carbon for the agricultural and chemical sectors. However, the industrial transformation of N2, CO2, and CO and the production of H2 require significant energy input, which renders processes like steam reforming and the Haber-Bosch reaction economically and environmentally unviable. Nature, on the other hand, performs similar tasks efficiently at ambient temperature and pressure, exploiting gas-processing metalloenzymes (GPMs) that bind low-valent metal cofactors based on iron, nickel, molybdenum, tungsten, and sulfur. Such systems are studied to understand the biocatalytic principles of gas conversion including N2 fixation by nitrogenase and H2 production by hydrogenase as well as CO2 and CO conversion by formate dehydrogenase, carbon monoxide dehydrogenase, and nitrogenase. In this review, we emphasize the importance of the cofactor/protein interface, discussing how second and outer coordination sphere effects determine, modulate, and optimize the catalytic activity of GPMs. These may comprise ionic interactions in the second coordination sphere that shape the electron density distribution across the cofactor, hydrogen bonding changes, and allosteric effects. In the outer coordination sphere, proton transfer and electron transfer are discussed, alongside the role of hydrophobic substrate channels and protein structural changes. Combining the information gained from structural biology, enzyme kinetics, and various spectroscopic techniques, we aim toward a comprehensive understanding of catalysis beyond the first coordination sphere.
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Affiliation(s)
- Sven T Stripp
- Freie Universität Berlin, Experimental Molecular Biophysics, Berlin 14195, Germany
| | | | - Vincent Fourmond
- Laboratoire de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Institut Microbiologie, Bioénergies et Biotechnologie, CNRS, Aix Marseille Université, Marseille 13402, France
| | - Christophe Léger
- Laboratoire de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Institut Microbiologie, Bioénergies et Biotechnologie, CNRS, Aix Marseille Université, Marseille 13402, France
| | - Silke Leimkühler
- University of Potsdam, Molecular Enzymology, Potsdam 14476, Germany
| | - Shun Hirota
- Nara Institute of Science and Technology, Division of Materials Science, Graduate School of Science and Technology, Nara 630-0192, Japan
| | - Yilin Hu
- Department of Molecular Biology & Biochemistry, University of California, Irvine, California 92697-3900, United States
| | - Andrew Jasniewski
- Department of Molecular Biology & Biochemistry, University of California, Irvine, California 92697-3900, United States
| | - Hideaki Ogata
- Nara Institute of Science and Technology, Division of Materials Science, Graduate School of Science and Technology, Nara 630-0192, Japan.,Hokkaido University, Institute of Low Temperature Science, Sapporo 060-0819, Japan.,Graduate School of Science, University of Hyogo, Hyogo 678-1297, Japan
| | - Markus W Ribbe
- Department of Molecular Biology & Biochemistry, University of California, Irvine, California 92697-3900, United States.,Department of Chemistry, University of California, Irvine, California 92697-2025, United States
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9
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Senger M, Duan J, Pavliuk MV, Apfel UP, Haumann M, Stripp ST. Trapping an Oxidized and Protonated Intermediate of the [FeFe]-Hydrogenase Cofactor under Mildly Reducing Conditions. Inorg Chem 2022; 61:10036-10042. [PMID: 35729755 DOI: 10.1021/acs.inorgchem.2c00954] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The H-cluster is the catalytic cofactor of [FeFe]-hydrogenase, a metalloenzyme that catalyzes the formation of dihydrogen (H2). The catalytic diiron site of the H-cluster carries two cyanide and three carbon monoxide ligands, making it an excellent target for IR spectroscopy. In previous work, we identified an oxidized and protonated H-cluster species, whose IR signature differs from that of the oxidized resting state (Hox) by a small but distinct shift to higher frequencies. This "blue shift" was explained by a protonation at the [4Fe-4S] subcomplex of the H-cluster. The novel species, denoted HoxH, was preferentially accumulated at low pH and in the presence of the exogenous reductant sodium dithionite (NaDT). When HoxH was reacted with H2, the hydride state (Hhyd) was formed, a key intermediate of [FeFe]-hydrogenase turnover. A recent publication revisited our protocol for the accumulation of HoxH in wild-type [FeFe]-hydrogenase, concluding that inhibition by NaDT decay products rather than cofactor protonation causes the spectroscopic "blue shift". Here, we demonstrate that HoxH formation does not require the presence of NaDT (or its decay products), but accumulates also with the milder reductants tris(2-carboxyethyl)phosphine, dithiothreitol, or ascorbic acid, in particular at low pH. Our data consistently suggest that HoxH is accumulated when deprotonation of the H-cluster is impaired, thereby preventing the regain of the oxidized resting state Hox in the catalytic cycle.
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Affiliation(s)
- Moritz Senger
- Department of Chemistry, Physical Chemistry, Uppsala University, Uppsala 75120, Sweden
| | - Jifu Duan
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-Universität Bochum, Bochum 44801, Germany
| | - Mariia V Pavliuk
- Department of Chemistry, Physical Chemistry, Uppsala University, Uppsala 75120, Sweden
| | - Ulf-Peter Apfel
- Faculty of Chemistry and Biochemistry, Small Molecule Activation, Ruhr-Universität Bochum, Bochum 44801, Germany.,Electrosynthesis, Fraunhofer UMSICHT, Oberhausen 46047, Germany
| | - Michael Haumann
- Department of Physics, Biophysics of Metalloenzymes, Freie Universität Berlin, Berlin 14195, Germany
| | - Sven T Stripp
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Berlin 14195, Germany
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10
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Affiliation(s)
- Sven T. Stripp
- Freie Universität Berlin, Department of Physics, Arnimallee 14, 14195 Berlin, Germany
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11
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Rohde M, Laun K, Zebger I, Stripp ST, Einsle O. Two ligand-binding sites in CO-reducing V nitrogenase reveal a general mechanistic principle. Sci Adv 2021; 7:7/22/eabg4474. [PMID: 34049880 PMCID: PMC8163085 DOI: 10.1126/sciadv.abg4474] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 04/14/2021] [Indexed: 06/12/2023]
Abstract
Besides its role in biological nitrogen fixation, vanadium-containing nitrogenase also reduces carbon monoxide (CO) to hydrocarbons, in analogy to the industrial Fischer-Tropsch process. The protein yields 93% of ethylene (C2H4), implying a C-C coupling step that mandates the simultaneous binding of two CO at the active site FeV cofactor. Spectroscopic data indicated multiple CO binding events, but structural analyses of Mo and V nitrogenase only confirmed a single site. Here, we report the structure of a two CO-bound state of V nitrogenase at 1.05 Å resolution, with one μ-bridging and one terminal CO molecule. This additional, specific ligand binding site suggests a mechanistic route for CO reduction and hydrocarbon formation, as well as a second access pathway for protons required during the reaction. Moreover, carbonyls are strong-field ligands that are chemically similar to mechanistically relevant hydrides that may be formed and used in a fully analogous fashion.
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Affiliation(s)
- Michael Rohde
- Institute for Biochemistry, University of Freiburg, Albertstrasse 21, 79104 Freiburg, Germany
| | - Konstantin Laun
- Institute of Chemistry, Technical University of Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Ingo Zebger
- Institute of Chemistry, Technical University of Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Sven T Stripp
- Institute of Experimental Physics, Department of Physics, Free University of Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Oliver Einsle
- Institute for Biochemistry, University of Freiburg, Albertstrasse 21, 79104 Freiburg, Germany.
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12
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Baserga F, Dragelj J, Kozuch J, Mohrmann H, Knapp EW, Stripp ST, Heberle J. Quantification of Local Electric Field Changes at the Active Site of Cytochrome c Oxidase by Fourier Transform Infrared Spectroelectrochemical Titrations. Front Chem 2021; 9:669452. [PMID: 33987170 PMCID: PMC8111224 DOI: 10.3389/fchem.2021.669452] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 03/24/2021] [Indexed: 11/30/2022] Open
Abstract
Cytochrome c oxidase (CcO) is a transmembrane protein complex that reduces molecular oxygen to water while translocating protons across the mitochondrial membrane. Changes in the redox states of its cofactors trigger both O2 reduction and vectorial proton transfer, which includes a proton-loading site, yet unidentified. In this work, we exploited carbon monoxide (CO) as a vibrational Stark effect (VSE) probe at the binuclear center of CcO from Rhodobacter sphaeroides. The CO stretching frequency was monitored as a function of the electrical potential, using Fourier transform infrared (FTIR) absorption spectroelectrochemistry. We observed three different redox states (R4CO, R2CO, and O), determined their midpoint potential, and compared the resulting electric field to electrostatic calculations. A change in the local electric field strength of +2.9 MV/cm was derived, which was induced by the redox transition from R4CO to R2CO. We performed potential jump experiments to accumulate the R2CO and R4CO species and studied the FTIR difference spectra in the protein fingerprint region. The comparison of the experimental and computational results reveals that the key glutamic acid residue E286 is protonated in the observed states, and that its hydrogen-bonding environment is disturbed upon the redox transition of heme a3. Our experiments also suggest propionate A of heme a3 changing its protonation state in concert with the redox state of a second cofactor, heme a. This supports the role of propionic acid side chains as part of the proton-loading site.
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Affiliation(s)
- Federico Baserga
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Jovan Dragelj
- Macromolecular Modelling Group, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany.,Modeling of Biomolecular Systems, Technische Universität Berlin, Berlin, Germany
| | - Jacek Kozuch
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Hendrik Mohrmann
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Ernst-Walter Knapp
- Macromolecular Modelling Group, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Sven T Stripp
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Joachim Heberle
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
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13
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Khushvakov J, Nussbaum R, Cadoux C, Duan J, Stripp ST, Milton RD. Following Electroenzymatic Hydrogen Production by Rotating Ring-Disk Electrochemistry and Mass Spectrometry*. Angew Chem Int Ed Engl 2021; 60:10001-10006. [PMID: 33630389 DOI: 10.1002/anie.202100863] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Indexed: 11/06/2022]
Abstract
Gas-processing metalloenzymes are of interest to future bio- and bioinspired technologies. Of particular importance are hydrogenases and nitrogenases, which both produce molecular hydrogen (H2 ) from proton (H+ ) reduction. Herein, we report on the use of rotating ring-disk electrochemistry (RRDE) and mass spectrometry (MS) to follow the production of H2 and isotopes produced from deuteron (D+ ) reduction (HD and D2 ) using the [FeFe]-hydrogenase from Clostridium pasteurianum, a model hydrogen-evolving metalloenzyme. This facilitates enzymology studies independent of non-innocent chemical reductants. We anticipate that these approaches will be of value in resolving the catalytic mechanisms of H2 -producing metalloenzymes and the design of bioinspired catalysts for H2 production and N2 fixation.
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Affiliation(s)
- Jaloliddin Khushvakov
- Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, 1211, Geneva 4, Switzerland
| | - Robin Nussbaum
- Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, 1211, Geneva 4, Switzerland
| | - Cécile Cadoux
- Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, 1211, Geneva 4, Switzerland
| | - Jifu Duan
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - Sven T Stripp
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, 10623, Berlin, Germany
| | - Ross D Milton
- Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, 1211, Geneva 4, Switzerland
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14
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Khushvakov J, Nussbaum R, Cadoux C, Duan J, Stripp ST, Milton RD. Untersuchung elektroenzymatischer H
2
‐Produktion mithilfe von Rotierende‐Ring‐Scheiben‐Elektrochemie und Massenspektrometrie**. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202100863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jaloliddin Khushvakov
- Department of Inorganic and Analytical Chemistry University of Geneva Quai Ernest-Ansermet 30 1211 Geneva 4 Schweiz
| | - Robin Nussbaum
- Department of Inorganic and Analytical Chemistry University of Geneva Quai Ernest-Ansermet 30 1211 Geneva 4 Schweiz
| | - Cécile Cadoux
- Department of Inorganic and Analytical Chemistry University of Geneva Quai Ernest-Ansermet 30 1211 Geneva 4 Schweiz
| | - Jifu Duan
- Faculty of Biology and Biotechnology, Photobiotechnology Ruhr-Universität Bochum Universitätsstraße 150 44801 Bochum Deutschland
| | - Sven T. Stripp
- Department of Physics, Experimental Molecular Biophysics Freie Universität Berlin 10623 Berlin Deutschland
| | - Ross D. Milton
- Department of Inorganic and Analytical Chemistry University of Geneva Quai Ernest-Ansermet 30 1211 Geneva 4 Schweiz
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15
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Laun K, Baranova I, Duan J, Kertess L, Wittkamp F, Apfel UP, Happe T, Senger M, Stripp ST. Site-selective protonation of the one-electron reduced cofactor in [FeFe]-hydrogenase. Dalton Trans 2021; 50:3641-3650. [PMID: 33629081 DOI: 10.1039/d1dt00110h] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hydrogenases are bidirectional redox enzymes that catalyze hydrogen turnover in archaea, bacteria, and algae. While all types of hydrogenase show H2 oxidation activity, [FeFe]-hydrogenases are excellent H2 evolution catalysts as well. Their active site cofactor comprises a [4Fe-4S] cluster covalently linked to a diiron site equipped with carbon monoxide and cyanide ligands. The active site niche is connected with the solvent by two distinct proton transfer pathways. To analyze the catalytic mechanism of [FeFe]-hydrogenase, we employ operando infrared spectroscopy and infrared spectro-electrochemistry. Titrating the pH under H2 oxidation or H2 evolution conditions reveals the influence of site-selective protonation on the equilibrium of reduced cofactor states. Governed by pKa differences across the active site niche and proton transfer pathways, we find that individual electrons are stabilized either at the [4Fe-4S] cluster (alkaline pH values) or at the diiron site (acidic pH values). This observation is discussed in the context of the complex interdependence of hydrogen turnover and bulk pH.
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Affiliation(s)
- Konstantin Laun
- Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany. sven.stripp@fu-berlin and Department of Chemistry, Technische Universität Berlin, 10623 Berlin, Germany
| | - Iuliia Baranova
- Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany. sven.stripp@fu-berlin and Faculty of Physics, St. Petersburg State University, 198504 St. Petersburg, Russian Federation
| | - Jifu Duan
- Faculty of Biology and Biotechnology, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Leonie Kertess
- Faculty of Biology and Biotechnology, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Florian Wittkamp
- Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Ulf-Peter Apfel
- Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, 44801 Bochum, Germany and Fraunhofer UMSICHT, 46047 Oberhausen, Germany
| | - Thomas Happe
- Faculty of Biology and Biotechnology, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Moritz Senger
- Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany. sven.stripp@fu-berlin and Department of Chemistry, Uppsala University, 75120 Uppsala, Sweden.
| | - Sven T Stripp
- Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany. sven.stripp@fu-berlin
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16
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Abstract
Hydrogenases are metalloenzymes that catalyze proton reduction and H2 oxidation with outstanding efficiency. They are model systems for bioinorganic chemistry, including low-valent transition metals, hydride chemistry, and proton-coupled electron transfer. In this Account, we describe how photochemistry and infrared difference spectroscopy can be used to identify the dynamic hydrogen-bonding changes that facilitate proton transfer in [NiFe]- and [FeFe]-hydrogenase.[NiFe]-hydrogenase binds a heterobimetallic nickel/iron site embedded in the protein by four cysteine ligands. [FeFe]-hydrogenase carries a homobimetallic iron/iron site attached to the protein by only a single cysteine. Carbon monoxide and cyanide ligands in the active site facilitate detailed investigations of hydrogenase catalysis by infrared spectroscopy because of their strong signals and redox-dependent frequency shifts. We found that specific redox-state transitions in [NiFe]- and [FeFe]-hydrogenase can be triggered by visible light to record extremely sensitive "light-minus-dark" infrared difference spectra monitoring key amino acid residues. As these transitions are coupled to protonation changes, our data allowed investigation of dynamic hydrogen-bonding changes that go well beyond the resolution of protein crystallography.In [NiFe]-hydrogenase, photolysis of the bridging hydride ligand in the Ni-C state was followed by infrared difference spectroscopy. Our data clearly indicate the formation of a protonated cysteine residue as well as hydrogen-bonding changes involving a glutamic acid residue and a "dangling water" molecule. These findings are in excellent agreement with crystallographic analyses of [NiFe]-hydrogenase. In [FeFe]-hydrogenase, an external redox dye was used to accumulate the Hred state. Infrared difference spectra indicate hydrogen-bonding changes involving two glutamic acid residues and a conserved arginine residue. While crystallographic analyses of [FeFe]-hydrogenase in the oxidized state failed to explain the rapid proton transfer because of a breach in the succession of residues, our findings facilitated a precise molecular model of discontinued proton transfer.Comparing both systems, our data emphasize the role of the outer coordination sphere in bimetallic hydrogenases: we suggest that protonation of a nickel-ligating cysteine in [NiFe]-hydrogenase causes the notable preference toward H2 oxidation. On the contrary, proton transfer in [FeFe]-hydrogenase involves an adjacent cysteine as a relay group, promoting both H2 oxidation and proton reduction. These observations may guide the design of organometallic compounds that mimic the catalytic properties of hydrogenases.
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Affiliation(s)
- Hulin Tai
- Department of Chemistry, National Demonstration Centre for Experimental Chemistry Education, Yanbian University, Yanji, Jilin 133002, China
| | - Shun Hirota
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Sven T. Stripp
- Bioinorganic Spectroscopy, Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany
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17
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Abul-Futouh H, Almazahreh LR, Abaalkhail SJ, Görls H, Stripp ST, Weigand W. Ligand effects on structural, protophilic and reductive features of stannylated dinuclear iron dithiolato complexes. NEW J CHEM 2021. [DOI: 10.1039/d0nj04790b] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis and characterization of Fe2(CO)5(L){μ-(SCH2)2SnMe2} (L = PPh3 (2) and P(OMe)3 (3)) derived from the parent hexacarbonyl complex Fe2(CO)6{μ-(SCH2)2}SnMe2 (1) are reported.
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Affiliation(s)
- Hassan Abul-Futouh
- Department of Pharmacy
- Al-Zaytoonah University of Jordan
- Amman 11733
- Jordan
| | - Laith R. Almazahreh
- ERCOSPLAN Ingenieurbüro Anlagentechnik GmbH
- 99096 Erfurt
- Germany
- Institut für Anorganische und Analytische Chemie
- Friedrich-Schiller-Universität Jena
| | - Sara J. Abaalkhail
- Department of Pharmacy
- Al-Zaytoonah University of Jordan
- Amman 11733
- Jordan
| | - Helmar Görls
- Institut für Anorganische und Analytische Chemie
- Friedrich-Schiller-Universität Jena
- 07743 Jena
- Germany
| | - Sven T. Stripp
- Bioinorganic Spectroscopy
- Department of Physics
- Freie Universität Berlin
- 1495 Berlin
- Germany
| | - Wolfgang Weigand
- Institut für Anorganische und Analytische Chemie
- Friedrich-Schiller-Universität Jena
- 07743 Jena
- Germany
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18
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Abstract
[FeFe]-hydrogenases are nature's blueprint for efficient hydrogen turnover. Understanding their enzymatic mechanism may improve technological H2 fuel generation. The active-site cofactor (H-cluster) consists of a [4Fe-4S] cluster ([4Fe]H), cysteine-linked to a diiron site ([2Fe]H) carrying an azadithiolate (adt) group, terminal cyanide and carbon monoxide ligands, and a bridging carbon monoxide (μCO) in the oxidized protein (Hox). Recently, the debate on the structure of reduced H-cluster states was intensified by the assignment of new species under cryogenic conditions. We investigated temperature effects (4-280 K) in infrared (IR) and X-ray absorption spectroscopy (XAS) data of [FeFe]-hydrogenases using fit analyses and quantum-chemical calculations. IR data from our laboratory and literature sources were evaluated. At ambient temperatures, reduced H-cluster states with a bridging hydride (μH-, in Hred and Hsred) or with an additional proton at [4Fe]H (Hred') or at the distal iron of [2Fe]H (Hhyd) prevail. At cryogenic temperatures, these species are largely replaced by states that hold a μCO, lack [4Fe]H protonation, and bind an additional proton at the adt nitrogen (HredH+ and HsredH+). XAS revealed the atomic coordinate dispersion (i.e., the Debye-Waller parameter, 2σ2) of the iron-ligand bonds and Fe-Fe distances in the oxidized and reduced H-cluster. 2σ2 showed a temperature dependence typical for the so-called protein-glass transition, with small changes below ∼200 K and a pronounced increase above this "breakpoint". This behavior is attributed to the freezing-out of larger-scale anharmonic motions of amino acid side chains and water species. We propose that protonation at [4Fe]H as well as ligand rearrangement and μH- binding at [2Fe]H are impaired because of restricted molecular mobility at cryogenic temperatures so that protonation can be biased toward adt. We conclude that a H-cluster with a μCO, selective [4Fe]H or [2Fe]H protonation, and catalytic proton transfer via adt facilitates efficient H2 conversion in [FeFe]-hydrogenase.
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Affiliation(s)
- Sven T Stripp
- Physics Department, Freie Universität Berlin, Arnimallee 14, Berlin 14195, Germany
| | - Stefan Mebs
- Physics Department, Freie Universität Berlin, Arnimallee 14, Berlin 14195, Germany
| | - Michael Haumann
- Physics Department, Freie Universität Berlin, Arnimallee 14, Berlin 14195, Germany
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19
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Land H, Sekretareva A, Huang P, Redman HJ, Németh B, Polidori N, Mészáros LS, Senger M, Stripp ST, Berggren G. Characterization of a putative sensory [FeFe]-hydrogenase provides new insight into the role of the active site architecture. Chem Sci 2020; 11:12789-12801. [PMID: 34094474 PMCID: PMC8163306 DOI: 10.1039/d0sc03319g] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 09/19/2020] [Indexed: 12/12/2022] Open
Abstract
[FeFe]-hydrogenases are known for their high rates of hydrogen turnover, and are intensively studied in the context of biotechnological applications. Evolution has generated a plethora of different subclasses with widely different characteristics. The M2e subclass is phylogenetically distinct from previously characterized members of this enzyme family and its biological role is unknown. It features significant differences in domain- and active site architecture, and is most closely related to the putative sensory [FeFe]-hydrogenases. Here we report the first comprehensive biochemical and spectroscopical characterization of an M2e enzyme, derived from Thermoanaerobacter mathranii. As compared to other [FeFe]-hydrogenases characterized to-date, this enzyme displays an increased H2 affinity, higher activation enthalpies for H+/H2 interconversion, and unusual reactivity towards known hydrogenase inhibitors. These properties are related to differences in active site architecture between the M2e [FeFe]-hydrogenase and "prototypical" [FeFe]-hydrogenases. Thus, this study provides new insight into the role of this subclass in hydrogen metabolism and the influence of the active site pocket on the chemistry of the H-cluster.
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Affiliation(s)
- Henrik Land
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
| | - Alina Sekretareva
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
| | - Ping Huang
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
| | - Holly J Redman
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
| | - Brigitta Németh
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
| | - Nakia Polidori
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
| | - Lívia S Mészáros
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
| | - Moritz Senger
- Physical Chemistry, Department of Chemistry, Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
- Bioinorganic Spectroscopy, Department of Physics, Freie Universität Berlin Arnimallee 14 DE-14195 Berlin Germany
| | - Sven T Stripp
- Bioinorganic Spectroscopy, Department of Physics, Freie Universität Berlin Arnimallee 14 DE-14195 Berlin Germany
| | - Gustav Berggren
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
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20
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Németh B, Senger M, Redman HJ, Ceccaldi P, Broderick J, Magnuson A, Stripp ST, Haumann M, Berggren G. [FeFe]-hydrogenase maturation: H-cluster assembly intermediates tracked by electron paramagnetic resonance, infrared, and X-ray absorption spectroscopy. J Biol Inorg Chem 2020; 25:777-788. [PMID: 32661785 PMCID: PMC7399679 DOI: 10.1007/s00775-020-01799-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 06/09/2020] [Indexed: 11/25/2022]
Abstract
[FeFe]-hydrogenase enzymes employ a unique organometallic cofactor for efficient and reversible hydrogen conversion. This so-called H-cluster consists of a [4Fe-4S] cubane cysteine linked to a diiron complex coordinated by carbon monoxide and cyanide ligands and an azadithiolate ligand (adt = NH(CH2S)2)·[FeFe]-hydrogenase apo-protein binding only the [4Fe-4S] sub-complex can be fully activated in vitro by the addition of a synthetic diiron site precursor complex ([2Fe]adt). Elucidation of the mechanism of cofactor assembly will aid in the design of improved hydrogen processing synthetic catalysts. We combined electron paramagnetic resonance, Fourier-transform infrared, and X-ray absorption spectroscopy to characterize intermediates of H-cluster assembly as initiated by mixing of the apo-protein (HydA1) from the green alga Chlamydomonas reinhardtii with [2Fe]adt. The three methods consistently show rapid formation of a complete H-cluster in the oxidized, CO-inhibited state (Hox-CO) already within seconds after the mixing. Moreover, FTIR spectroscopy support a model in which Hox-CO formation is preceded by a short-lived Hred'-CO-like intermediate. Accumulation of Hox-CO was followed by CO release resulting in the slower conversion to the catalytically active state (Hox) as well as formation of reduced states of the H-cluster.
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Affiliation(s)
- Brigitta Németh
- Department of Chemistry, Ångström Laboratory, Molecular Biomimetics, Uppsala University, 75120, Uppsala, Sweden
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Moritz Senger
- Physics Department, Molecular Biophysics, Freie Universität Berlin, 14195, Berlin, Germany
- Department of Chemistry, Ångström Laboratory, Physical Chemistry, Uppsala University, 75120, Uppsala, Sweden
| | - Holly J Redman
- Department of Chemistry, Ångström Laboratory, Molecular Biomimetics, Uppsala University, 75120, Uppsala, Sweden
| | - Pierre Ceccaldi
- Department of Chemistry, Ångström Laboratory, Molecular Biomimetics, Uppsala University, 75120, Uppsala, Sweden
| | - Joan Broderick
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Ann Magnuson
- Department of Chemistry, Ångström Laboratory, Molecular Biomimetics, Uppsala University, 75120, Uppsala, Sweden
| | - Sven T Stripp
- Physics Department, Molecular Biophysics, Freie Universität Berlin, 14195, Berlin, Germany
| | - Michael Haumann
- Physics Department, Biophysics of Metalloenzymes, Freie Universität Berlin, 14195, Berlin, Germany
| | - Gustav Berggren
- Department of Chemistry, Ångström Laboratory, Molecular Biomimetics, Uppsala University, 75120, Uppsala, Sweden.
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21
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Affiliation(s)
- Henrik Land
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala 75120, Sweden
| | - Moritz Senger
- Physical Chemistry, Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala 75120, Sweden
- Bioinorganic Spectroscopy, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Gustav Berggren
- Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala 75120, Sweden
| | - Sven T. Stripp
- Bioinorganic Spectroscopy, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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22
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Mészáros LS, Ceccaldi P, Lorenzi M, Redman HJ, Pfitzner E, Heberle J, Senger M, Stripp ST, Berggren G. Spectroscopic investigations under whole-cell conditions provide new insight into the metal hydride chemistry of [FeFe]-hydrogenase. Chem Sci 2020; 11:4608-4617. [PMID: 34122916 PMCID: PMC8159234 DOI: 10.1039/d0sc00512f] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Hydrogenases are among the fastest H2 evolving catalysts known to date and have been extensively studied under in vitro conditions. Here, we report the first mechanistic investigation of an [FeFe]-hydrogenase under whole-cell conditions. Functional [FeFe]-hydrogenase from the green alga Chlamydomonas reinhardtii is generated in genetically modified Escherichia coli cells by addition of a synthetic cofactor to the growth medium. The assembly and reactivity of the resulting semi-synthetic enzyme was monitored using whole-cell electron paramagnetic resonance and Fourier-transform Infrared difference spectroscopy as well as scattering scanning near-field optical microscopy. Through a combination of gas treatments, pH titrations, and isotope editing we were able to corroborate the formation of a number of proposed catalytic intermediates in living cells, supporting their physiological relevance. Moreover, a previously incompletely characterized catalytic intermediate is reported herein, attributed to the formation of a protonated metal hydride species.
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Affiliation(s)
- Lívia S Mészáros
- Molecular Biomimetics, Dept. of Chemistry - Ångström Laboratory, Uppsala University Lägerhyddsvägen 1 SE-75120 Uppsala Sweden
| | - Pierre Ceccaldi
- Molecular Biomimetics, Dept. of Chemistry - Ångström Laboratory, Uppsala University Lägerhyddsvägen 1 SE-75120 Uppsala Sweden
| | - Marco Lorenzi
- Molecular Biomimetics, Dept. of Chemistry - Ångström Laboratory, Uppsala University Lägerhyddsvägen 1 SE-75120 Uppsala Sweden
| | - Holly J Redman
- Molecular Biomimetics, Dept. of Chemistry - Ångström Laboratory, Uppsala University Lägerhyddsvägen 1 SE-75120 Uppsala Sweden
| | - Emanuel Pfitzner
- Institute of Experimental Physics, Experimental Molecular Biophysics, Freie Universität Berlin Arnimallee 14 Berlin DE-14195 Germany
| | - Joachim Heberle
- Institute of Experimental Physics, Experimental Molecular Biophysics, Freie Universität Berlin Arnimallee 14 Berlin DE-14195 Germany
| | - Moritz Senger
- Institute of Experimental Physics, Experimental Molecular Biophysics, Freie Universität Berlin Arnimallee 14 Berlin DE-14195 Germany
| | - Sven T Stripp
- Institute of Experimental Physics, Experimental Molecular Biophysics, Freie Universität Berlin Arnimallee 14 Berlin DE-14195 Germany
| | - Gustav Berggren
- Molecular Biomimetics, Dept. of Chemistry - Ångström Laboratory, Uppsala University Lägerhyddsvägen 1 SE-75120 Uppsala Sweden
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23
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Land H, Ceccaldi P, Mészáros LS, Lorenzi M, Redman HJ, Senger M, Stripp ST, Berggren G. Discovery of novel [FeFe]-hydrogenases for biocatalytic H 2-production. Chem Sci 2019; 10:9941-9948. [PMID: 32055351 PMCID: PMC6984386 DOI: 10.1039/c9sc03717a] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Accepted: 09/23/2019] [Indexed: 11/21/2022] Open
Abstract
A semi-synthetic screening method for mining the biodiversity of [FeFe]-hydrogenases, expanding the toolbox for biocatalytic H2-gas production.
A new screening method for [FeFe]-hydrogenases is described, circumventing the need for specialized expression conditions as well as protein purification for initial characterization. [FeFe]-hydrogenases catalyze the formation and oxidation of molecular hydrogen at rates exceeding 103 s–1, making them highly promising for biotechnological applications. However, the discovery of novel [FeFe]-hydrogenases is slow due to their oxygen sensitivity and dependency on a structurally unique cofactor, complicating protein expression and purification. Consequently, only a very limited number have been characterized, hampering their implementation. With the purpose of increasing the throughput of [FeFe]-hydrogenase discovery, we have developed a screening method that allows for rapid identification of novel [FeFe]-hydrogenases as well as their characterization with regards to activity (activity assays and protein film electrochemistry) and spectroscopic properties (electron paramagnetic resonance and Fourier transform infrared spectroscopy). The method is based on in vivo artificial maturation of [FeFe]-hydrogenases in Escherichia coli and all procedures are performed on either whole cells or non-purified cell lysates, thereby circumventing extensive protein purification. The screening was applied on eight putative [FeFe]-hydrogenases originating from different structural sub-classes and resulted in the discovery of two new active [FeFe]-hydrogenases. The [FeFe]-hydrogenase from Solobacterium moorei shows high H2-gas production activity, while the enzyme from Thermoanaerobacter mathranii represents a hitherto uncharacterized [FeFe]-hydrogenase sub-class. This latter enzyme is a putative sensory hydrogenase and our in vivo spectroscopy study reveals distinct differences compared to the well established H2 producing HydA1 hydrogenase from Chlamydomonas reinhardtii.
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Affiliation(s)
- Henrik Land
- Molecular Biomimetics , Department of Chemistry - Ångström Laboratory , Uppsala University , Box 523 , Uppsala , SE-75120 , Sweden .
| | - Pierre Ceccaldi
- Molecular Biomimetics , Department of Chemistry - Ångström Laboratory , Uppsala University , Box 523 , Uppsala , SE-75120 , Sweden .
| | - Lívia S Mészáros
- Molecular Biomimetics , Department of Chemistry - Ångström Laboratory , Uppsala University , Box 523 , Uppsala , SE-75120 , Sweden .
| | - Marco Lorenzi
- Molecular Biomimetics , Department of Chemistry - Ångström Laboratory , Uppsala University , Box 523 , Uppsala , SE-75120 , Sweden .
| | - Holly J Redman
- Molecular Biomimetics , Department of Chemistry - Ångström Laboratory , Uppsala University , Box 523 , Uppsala , SE-75120 , Sweden .
| | - Moritz Senger
- Institute of Experimental Physics, Experimental Molecular Biophysics , Freie Universität Berlin , Arnimallee 14 , Berlin , DE-14195 , Germany
| | - Sven T Stripp
- Institute of Experimental Physics, Experimental Molecular Biophysics , Freie Universität Berlin , Arnimallee 14 , Berlin , DE-14195 , Germany
| | - Gustav Berggren
- Molecular Biomimetics , Department of Chemistry - Ångström Laboratory , Uppsala University , Box 523 , Uppsala , SE-75120 , Sweden .
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24
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Duan J, Mebs S, Laun K, Wittkamp F, Heberle J, Happe T, Hofmann E, Apfel UP, Winkler M, Senger M, Haumann M, Stripp ST. Geometry of the Catalytic Active Site in [FeFe]-Hydrogenase Is Determined by Hydrogen Bonding and Proton Transfer. ACS Catal 2019. [DOI: 10.1021/acscatal.9b02203] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Jifu Duan
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Stefan Mebs
- Department of Physics, Biophysics of Metalloenzymes, Freie Universität Berlin, 14195 Berlin, Germany
| | - Konstantin Laun
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Florian Wittkamp
- Faculty of Chemistry and Biochemistry, Inorganic Chemistry I, Ruhr University Bochum, 44801 Bochum, Germany
| | - Joachim Heberle
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Thomas Happe
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Eckhard Hofmann
- Faculty of Biology and Biotechnology, Protein Crystallography, Ruhr University Bochum, 44801 Bochum, Germany
| | - Ulf-Peter Apfel
- Faculty of Chemistry and Biochemistry, Inorganic Chemistry I, Ruhr University Bochum, 44801 Bochum, Germany
- Fraunhofer UMSICHT, 46047 Oberhausen, Germany
| | - Martin Winkler
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Moritz Senger
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Michael Haumann
- Department of Physics, Biophysics of Metalloenzymes, Freie Universität Berlin, 14195 Berlin, Germany
| | - Sven T. Stripp
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, 14195 Berlin, Germany
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Mebs S, Duan J, Wittkamp F, Stripp ST, Happe T, Apfel UP, Winkler M, Haumann M. Differential Protonation at the Catalytic Six-Iron Cofactor of [FeFe]-Hydrogenases Revealed by 57Fe Nuclear Resonance X-ray Scattering and Quantum Mechanics/Molecular Mechanics Analyses. Inorg Chem 2019; 58:4000-4013. [PMID: 30802044 DOI: 10.1021/acs.inorgchem.9b00100] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[FeFe]-hydrogenases are efficient biological hydrogen conversion catalysts and blueprints for technological fuel production. The relations between substrate interactions and electron/proton transfer events at their unique six-iron cofactor (H-cluster) need to be elucidated. The H-cluster comprises a four-iron cluster, [4Fe4S], linked to a diiron complex, [FeFe]. We combined 57Fe-specific X-ray nuclear resonance scattering experiments (NFS, nuclear forward scattering; NRVS, nuclear resonance vibrational spectroscopy) with quantum-mechanics/molecular-mechanics computations to study the [FeFe]-hydrogenase HYDA1 from a green alga. Selective 57Fe labeling at only [4Fe4S] or [FeFe], or at both subcomplexes was achieved by protein expression with a 57Fe salt and in vitro maturation with a synthetic diiron site precursor containing 57Fe. H-cluster states were populated under infrared spectroscopy control. NRVS spectral analyses facilitated assignment of the vibrational modes of the cofactor species. This approach revealed the H-cluster structure of the oxidized state (Hox) with a bridging carbon monoxide at [FeFe] and ligand rearrangement in the CO-inhibited state (Hox-CO). Protonation at a cysteine ligand of [4Fe4S] in the oxidized state occurring at low pH (HoxH) was indicated, in contrast to bridging hydride binding at [FeFe] in a one-electron reduced state (Hred). These findings are direct evidence for differential protonation either at the four-iron or diiron subcomplex of the H-cluster. NFS time-traces provided Mössbauer parameters such as the quadrupole splitting energy, which differ among cofactor states, thereby supporting selective protonation at either subcomplex. In combination with data for reduced states showing similar [4Fe4S] protonation as HoxH without (Hred') or with (Hhyd) a terminal hydride at [FeFe], our results imply that coordination geometry dynamics at the diiron site and proton-coupled electron transfer to either the four-iron or the diiron subcomplex discriminate catalytic and regulatory functions of [FeFe]-hydrogenases. We support a reaction cycle avoiding diiron site geometry changes during rapid H2 turnover.
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Affiliation(s)
| | | | | | | | | | - Ulf-Peter Apfel
- Fraunhofer UMSICHT , Osterfelder Straße 3 , 46047 Oberhausen , Germany
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26
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Duan J, Senger M, Esselborn J, Engelbrecht V, Wittkamp F, Apfel UP, Hofmann E, Stripp ST, Happe T, Winkler M. Crystallographic and spectroscopic assignment of the proton transfer pathway in [FeFe]-hydrogenases. Nat Commun 2018; 9:4726. [PMID: 30413719 PMCID: PMC6226526 DOI: 10.1038/s41467-018-07140-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 10/18/2018] [Indexed: 11/29/2022] Open
Abstract
The unmatched catalytic turnover rates of [FeFe]-hydrogenases require an exceptionally efficient proton-transfer (PT) pathway to shuttle protons as substrates or products between bulk water and catalytic center. For clostridial [FeFe]-hydrogenase CpI such a pathway has been proposed and analyzed, but mainly on a theoretical basis. Here, eleven enzyme variants of two different [FeFe]-hydrogenases (CpI and HydA1) with substitutions in the presumptive PT-pathway are examined kinetically, spectroscopically, and crystallographically to provide solid experimental proof for its role in hydrogen-turnover. Targeting key residues of the PT-pathway by site directed mutagenesis significantly alters the pH-activity profile of these variants and in presence of H2 their cofactor is trapped in an intermediate state indicative of precluded proton-transfer. Furthermore, crystal structures coherently explain the individual levels of residual activity, demonstrating e.g. how trapped H2O molecules rescue the interrupted PT-pathway. These features provide conclusive evidence that the targeted positions are indeed vital for catalytic proton-transfer. [FeFe]-hydrogenases catalyze H2-evolution and -oxidation at very high turnover-rates. Here the authors provide experimental evidence for the proposed proton-transfer (PT) pathway by kinetically, spectroscopically, and crystallographically characterizing eleven mutants from the two [FeFe]-hydrogenases CpI and HydA1.
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Affiliation(s)
- Jifu Duan
- Department of Plant Biochemistry, Photobiotechnology, Ruhr-Universität Bochum, 44801, Bochum, Germany
| | - Moritz Senger
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, 14195, Berlin, Germany
| | - Julian Esselborn
- Department of Plant Biochemistry, Photobiotechnology, Ruhr-Universität Bochum, 44801, Bochum, Germany
| | - Vera Engelbrecht
- Department of Plant Biochemistry, Photobiotechnology, Ruhr-Universität Bochum, 44801, Bochum, Germany
| | - Florian Wittkamp
- Department of Chemistry and Biochemistry, Inorganic Chemistry Ι, Ruhr-Universität Bochum, 44801, Bochum, Germany
| | - Ulf-Peter Apfel
- Department of Chemistry and Biochemistry, Inorganic Chemistry Ι, Ruhr-Universität Bochum, 44801, Bochum, Germany.,Fraunhofer UMSICHT, Osterfelder Straße, 346047, Oberhausen, Germany
| | - Eckhard Hofmann
- Department of Biophysics, Protein Crystallography, Ruhr-Universität Bochum, 44801, Bochum, Germany
| | - Sven T Stripp
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, 14195, Berlin, Germany
| | - Thomas Happe
- Department of Plant Biochemistry, Photobiotechnology, Ruhr-Universität Bochum, 44801, Bochum, Germany.
| | - Martin Winkler
- Department of Plant Biochemistry, Photobiotechnology, Ruhr-Universität Bochum, 44801, Bochum, Germany.
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Abstract
Over the past two decades, the bioinorganic chemistry of hydrogenases has attracted much interest from basic and applied research. Hydrogenases are highly efficient metalloenzymes that catalyze the reversible reduction of protons to molecular hydrogen (H2) in all domains of life. Their iron- and nickel-based cofactors represent promising blueprints for the design of biomimetic, synthetic catalysts. In this Account, we address the molecular proceedings of hydrogen turnover with [FeFe]-hydrogenases. The active site cofactor of [FeFe]-hydrogenases ("H-cluster") comprises a unique diiron complex linked to a [4Fe-4S] cluster via a single cysteine. Since it was discovered that a synthetic analogue of the diiron site can be incorporated into apoprotein in vitro to yield active enzyme, significant progress has been made toward a comprehensive understanding of hydrogenase catalysis. The diiron site carries three to four carbon monoxide (CO) and two cyanide (CN-) ligands that give rise to intense infrared (IR) absorption bands. These bands are sensitive reporters of the electron density across the H-cluster, which can be addressed by infrared spectroscopy to follow redox and protonation changes at the cofactor. Synthetic variation of the metal-bridging dithiolate ligand at the diiron site, as well as site-directed mutagenesis of amino acids, provides access to the proton pathways toward the cofactor. Quantum chemical calculations are employed to specifically assign IR bands to vibrational modes of the diatomic ligands and yield refined H-cluster geometries. Here, we provide an overview of recent research on [FeFe]-hydrogenases with emphasis on experimental and computational IR studies. We describe advances in attenuated total reflection Fourier transform infrared spectroscopy (ATR FTIR) and protein film electrochemistry, as well as density functional theory (DFT) calculations. Key cofactor species are discussed in terms of molecular geometry, redox state, and protonation. Isotope editing is introduced as a tool to evaluate the cofactor geometry beyond the limits of protein crystallography. In particular, the role of proton-coupled electron transfer (PCET) in the generation of catalytically relevant redox species is addressed. We propose that site-selective protonation of the H-cluster biases surplus electrons either to the [4Fe-4S] cluster or to the diiron site. Protonation of the [4Fe-4S] cluster prevents premature reduction at the diiron site and stabilizes a reactive, terminal hydride. The observed H-cluster species are assigned to rapid H2 conversion or to reactions possibly involved in activity regulation and cellular H2 sensing. In the catalytic cycle of [FeFe]-hydrogenases, an H-cluster geometry is preserved that features a bridging CO ligand. PCET levels the redox potential for two steps of sequential cofactor reduction. The concept of consecutive PCET at a geometrically inert cofactor with tight control of electron and proton localization may inspire the design of a novel generation of biomimetic catalysts for the production of H2 as a fuel.
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Affiliation(s)
- Michael Haumann
- Department of Physics, Biophysics of Metalloenzymes, Freie Universität Berlin, 14195 Berlin, Germany
| | - Sven T. Stripp
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, 14195 Berlin, Germany
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Senger M, Mebs S, Duan J, Shulenina O, Laun K, Kertess L, Wittkamp F, Apfel UP, Happe T, Winkler M, Haumann M, Stripp ST. Protonation/reduction dynamics at the [4Fe-4S] cluster of the hydrogen-forming cofactor in [FeFe]-hydrogenases. Phys Chem Chem Phys 2018; 20:3128-3140. [PMID: 28884175 DOI: 10.1039/c7cp04757f] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The [FeFe]-hydrogenases of bacteria and algae are the most efficient hydrogen conversion catalysts in nature. Their active-site cofactor (H-cluster) comprises a [4Fe-4S] cluster linked to a unique diiron site that binds three carbon monoxide (CO) and two cyanide (CN-) ligands. Understanding microbial hydrogen conversion requires elucidation of the interplay of proton and electron transfer events at the H-cluster. We performed real-time spectroscopy on [FeFe]-hydrogenase protein films under controlled variation of atmospheric gas composition, sample pH, and reductant concentration. Attenuated total reflection Fourier-transform infrared spectroscopy was used to monitor shifts of the CO/CN- vibrational bands in response to redox and protonation changes. Three different [FeFe]-hydrogenases and several protein and cofactor variants were compared, including element and isotopic exchange studies. A protonated equivalent (HoxH) of the oxidized state (Hox) was found, which preferentially accumulated at acidic pH and under reducing conditions. We show that the one-electron reduced state Hred' represents an intrinsically protonated species. Interestingly, the formation of HoxH and Hred' was independent of the established proton pathway to the diiron site. Quantum chemical calculations of the respective CO/CN- infrared band patterns favored a cysteine ligand of the [4Fe-4S] cluster as the protonation site in HoxH and Hred'. We propose that proton-coupled electron transfer facilitates reduction of the [4Fe-4S] cluster and prevents premature formation of a hydride at the catalytic diiron site. Our findings imply that protonation events both at the [4Fe-4S] cluster and at the diiron site of the H-cluster are important in the hydrogen conversion reaction of [FeFe]-hydrogenases.
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Affiliation(s)
- Moritz Senger
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany.
| | - Stefan Mebs
- Department of Physics, Biophysics of Metalloenzymes, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
| | - Jifu Duan
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-Universität Bochum, 44801 Bochum, Germany.
| | - Olga Shulenina
- Faculty of Physics, St. Petersburg State University, 198504 St. Petersburg, Russian Federation
| | - Konstantin Laun
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany.
| | - Leonie Kertess
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-Universität Bochum, 44801 Bochum, Germany.
| | - Florian Wittkamp
- Faculty of Chemistry and Biochemistry, Inorganic Chemistry I, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Ulf-Peter Apfel
- Faculty of Chemistry and Biochemistry, Inorganic Chemistry I, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Thomas Happe
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-Universität Bochum, 44801 Bochum, Germany.
| | - Martin Winkler
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-Universität Bochum, 44801 Bochum, Germany.
| | - Michael Haumann
- Department of Physics, Biophysics of Metalloenzymes, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
| | - Sven T Stripp
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany.
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29
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Mebs S, Kositzki R, Duan J, Kertess L, Senger M, Wittkamp F, Apfel UP, Happe T, Stripp ST, Winkler M, Haumann M. Hydrogen and oxygen trapping at the H-cluster of [FeFe]-hydrogenase revealed by site-selective spectroscopy and QM/MM calculations. Biochimica et Biophysica Acta (BBA) - Bioenergetics 2018; 1859:28-41. [DOI: 10.1016/j.bbabio.2017.09.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 08/31/2017] [Accepted: 09/13/2017] [Indexed: 12/11/2022]
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30
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Senger M, Laun K, Wittkamp F, Duan J, Haumann M, Happe T, Winkler M, Apfel UP, Stripp ST. Protonengekoppelte Reduktion des katalytischen [4Fe-4S]-Zentrums in [FeFe]-Hydrogenasen. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201709910] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Moritz Senger
- Fakultät für Physik; Freie Universität Berlin; Arnimallee 14 1495 Berlin Deutschland
| | - Konstantin Laun
- Fakultät für Physik; Freie Universität Berlin; Arnimallee 14 1495 Berlin Deutschland
| | - Florian Wittkamp
- Fakultät für Chemie und Biochemie; Ruhr-Universität Bochum; Universitätstraße 150 44801 Bochum Deutschland
| | - Jifu Duan
- Fakultät für Biologie und Biotechnologie; Ruhr-Universität Bochum; Universitätsstraße 150 44801 Bochum Deutschland
| | - Michael Haumann
- Fakultät für Physik; Freie Universität Berlin; Arnimallee 14 1495 Berlin Deutschland
| | - Thomas Happe
- Fakultät für Biologie und Biotechnologie; Ruhr-Universität Bochum; Universitätsstraße 150 44801 Bochum Deutschland
| | - Martin Winkler
- Fakultät für Biologie und Biotechnologie; Ruhr-Universität Bochum; Universitätsstraße 150 44801 Bochum Deutschland
| | - Ulf-Peter Apfel
- Fakultät für Chemie und Biochemie; Ruhr-Universität Bochum; Universitätstraße 150 44801 Bochum Deutschland
| | - Sven T. Stripp
- Fakultät für Physik; Freie Universität Berlin; Arnimallee 14 1495 Berlin Deutschland
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31
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Senger M, Laun K, Wittkamp F, Duan J, Haumann M, Happe T, Winkler M, Apfel UP, Stripp ST. Proton-Coupled Reduction of the Catalytic [4Fe-4S] Cluster in [FeFe]-Hydrogenases. Angew Chem Int Ed Engl 2017; 56:16503-16506. [PMID: 29072356 DOI: 10.1002/anie.201709910] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 10/23/2017] [Indexed: 12/25/2022]
Abstract
In nature, [FeFe]-hydrogenases catalyze the uptake and release of molecular hydrogen (H2 ) at a unique iron-sulfur cofactor. The absence of an electrochemical overpotential in the H2 release reaction makes [FeFe]-hydrogenases a prime example of efficient biocatalysis. However, the molecular details of hydrogen turnover are not yet fully understood. Herein, we characterize the initial one-electron reduction of [FeFe]-hydrogenases by infrared spectroscopy and electrochemistry and present evidence for proton-coupled electron transport during the formation of the reduced state Hred'. Charge compensation stabilizes the excess electron at the [4Fe-4S] cluster and maintains a conservative configuration of the diiron site. The role of Hred' in hydrogen turnover and possible implications on the catalytic mechanism are discussed. We propose that regulation of the electronic properties in the periphery of metal cofactors is key to orchestrating multielectron processes.
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Affiliation(s)
- Moritz Senger
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 1495, Berlin, Germany
| | - Konstantin Laun
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 1495, Berlin, Germany
| | - Florian Wittkamp
- Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, Universitätstrasse 150, 44801, Bochum, Germany
| | - Jifu Duan
- Faculty of Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - Michael Haumann
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 1495, Berlin, Germany
| | - Thomas Happe
- Faculty of Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - Martin Winkler
- Faculty of Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - Ulf-Peter Apfel
- Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, Universitätstrasse 150, 44801, Bochum, Germany
| | - Sven T Stripp
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 1495, Berlin, Germany
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32
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Mohrmann H, Dragelj J, Baserga F, Knapp EW, Stripp ST, Heberle J. The reductive phase of Rhodobacter sphaeroides cytochrome c oxidase disentangled by CO ligation. Phys Chem Chem Phys 2017. [PMID: 29067359 DOI: 10.1039/c7cp06480b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cytochrome c oxidase (CcO) is a membrane protein of the respiratory chain that catalytically reduces molecular oxygen (O2) to water while translocating protons across the membrane. The enzyme hosts two copper and two heme iron moieties (heme a/heme a3). The atomic details of the sequential steps that go along with this redox-driven proton translocation are a matter of debate. Particularly for the reductive phase of CcO that precedes oxygen binding experimental data are scarce. Here, we use CcO under anaerobic conditions where carbon monoxide (CO) is bound to heme a3 which in tandem with CuB forms the binuclear center (BNC). Fourier-transform infrared (FTIR) absorption spectroscopy is combined with electro-chemistry to probe different redox and protonation states populated by variation of the external electrostatic potential. With this approach, the redox behavior of heme a and the BNC could be separated and the corresponding redox potentials were determined. We also infer the protonation of one of the propionate side chains of heme a3 to correlate with the oxidation of heme a. Experimental changes in the local electric field surrounding CO bound to heme a3 are determined by their vibrational Stark effect and agree well with electrostatic computations. The comparison of experimental and computational results indicates that changes of the heme a3/CuB redox state are coupled to proton transfer towards heme a3. The latter supports the role of the heme a3 propionate D as proton loading site.
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Affiliation(s)
- Hendrik Mohrmann
- Experimental Molecular Biophysics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
| | - Jovan Dragelj
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstraße 36A, 14195 Berlin, Germany
| | - Federico Baserga
- Experimental Molecular Biophysics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
| | - Ernst-Walter Knapp
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstraße 36A, 14195 Berlin, Germany
| | - Sven T Stripp
- Experimental Molecular Biophysics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
| | - Joachim Heberle
- Experimental Molecular Biophysics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
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Mebs S, Senger M, Duan J, Wittkamp F, Apfel UP, Happe T, Winkler M, Stripp ST, Haumann M. Bridging Hydride at Reduced H-Cluster Species in [FeFe]-Hydrogenases Revealed by Infrared Spectroscopy, Isotope Editing, and Quantum Chemistry. J Am Chem Soc 2017; 139:12157-12160. [PMID: 28825810 DOI: 10.1021/jacs.7b07548] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
[FeFe]-Hydrogenases contain a H2-converting cofactor (H-cluster) in which a canonical [4Fe-4S] cluster is linked to a unique diiron site with three carbon monoxide (CO) and two cyanide (CN-) ligands (e.g., in the oxidized state, Hox). There has been much debate whether reduction and hydrogen binding may result in alternative rotamer structures of the diiron site in a single (Hred) or double (Hsred) reduced H-cluster species. We employed infrared spectro-electrochemistry and site-selective isotope editing to monitor the CO/CN- stretching vibrations in [FeFe]-hydrogenase HYDA1 from Chlamydomonas reinhardtii. Density functional theory calculations yielded vibrational modes of the diatomic ligands for conceivable H-cluster structures. Correlation analysis of experimental and computational IR spectra has facilitated an assignment of Hred and Hsred to structures with a bridging hydride at the diiron site. Pronounced ligand rotation during μH binding seems to exclude Hred and Hsred as catalytic intermediates. Only states with a conservative H-cluster geometry featuring a μCO ligand are likely involved in rapid H2 turnover.
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Affiliation(s)
- Stefan Mebs
- Department of Physics, Biophysics of Metalloenzymes, Freie Universität Berlin , 14195 Berlin, Germany
| | - Moritz Senger
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin , 14195 Berlin, Germany
| | - Jifu Duan
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-Universität Bochum , 44801 Bochum, Germany
| | - Florian Wittkamp
- Faculty of Chemistry and Biochemistry, Bioinorganic Chemistry, Ruhr-Universität Bochum , 44801 Bochum, Germany
| | - Ulf-Peter Apfel
- Faculty of Chemistry and Biochemistry, Bioinorganic Chemistry, Ruhr-Universität Bochum , 44801 Bochum, Germany
| | - Thomas Happe
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-Universität Bochum , 44801 Bochum, Germany
| | - Martin Winkler
- Faculty of Biology and Biotechnology, Photobiotechnology, Ruhr-Universität Bochum , 44801 Bochum, Germany
| | - Sven T Stripp
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin , 14195 Berlin, Germany
| | - Michael Haumann
- Department of Physics, Biophysics of Metalloenzymes, Freie Universität Berlin , 14195 Berlin, Germany
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Senger M, Stripp ST, Soboh B. Proteolytic cleavage orchestrates cofactor insertion and protein assembly in [NiFe]-hydrogenase biosynthesis. J Biol Chem 2017; 292:11670-11681. [PMID: 28539366 DOI: 10.1074/jbc.m117.788125] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 05/23/2017] [Indexed: 01/07/2023] Open
Abstract
Metalloenzymes catalyze complex and essential processes, such as photosynthesis, respiration, and nitrogen fixation. For example, bacteria and archaea use [NiFe]-hydrogenases to catalyze the uptake and release of molecular hydrogen (H2). [NiFe]-hydrogenases are redox enzymes composed of a large subunit that harbors a NiFe(CN)2CO metallo-center and a small subunit with three iron-sulfur clusters. The large subunit is synthesized with a C-terminal extension, cleaved off by a specific endopeptidase during maturation. The exact role of the C-terminal extension has remained elusive; however, cleavage takes place exclusively after assembly of the [NiFe]-cofactor and before large and small subunits form the catalytically active heterodimer. To unravel the functional role of the C-terminal extension, we used an enzymatic in vitro maturation assay that allows synthesizing functional [NiFe]-hydrogenase-2 of Escherichia coli from purified components. The maturation process included formation and insertion of the NiFe(CN)2CO cofactor into the large subunit, endoproteolytic cleavage of the C-terminal extension, and dimerization with the small subunit. Biochemical and spectroscopic analysis indicated that the C-terminal extension of the large subunit is essential for recognition by the maturation machinery. Only upon completion of cofactor insertion was removal of the C-terminal extension observed. Our results indicate that endoproteolytic cleavage is a central checkpoint in the maturation process. Here, cleavage temporally orchestrates cofactor insertion and protein assembly and ensures that only cofactor-containing protein can continue along the assembly line toward functional [NiFe]-hydrogenase.
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Affiliation(s)
- Moritz Senger
- Department of Physics, Experimental Molecular Biophysics, Freie Universitaet Berlin, 14195 Berlin, Germany
| | - Sven T Stripp
- Department of Physics, Experimental Molecular Biophysics, Freie Universitaet Berlin, 14195 Berlin, Germany
| | - Basem Soboh
- Department of Physics, Experimental Molecular Biophysics, Freie Universitaet Berlin, 14195 Berlin, Germany.
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Mohrmann H, Dragelj J, Baserga F, Knapp EW, Stripp ST, Heberle J. Retraction: The reductive phase of Rhodobacter sphaeroides cytochrome c oxidase disentangled by CO ligation. Phys Chem Chem Phys 2017; 19:32143. [DOI: 10.1039/c7cp90263h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Retraction of ‘The reductive phase of Rhodobacter sphaeroides cytochrome c oxidase disentangled by CO ligation’ by Hendrik Mohrmann et al., Phys. Chem. Chem. Phys., 2017, DOI: 10.1039/c7cp06480b.
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Affiliation(s)
- Hendrik Mohrmann
- Experimental Molecular Biophysics
- Freie Universität Berlin
- 14195 Berlin
- Germany
| | - Jovan Dragelj
- Institute of Chemistry and Biochemistry
- Freie Universität Berlin
- 14195 Berlin
- Germany
| | - Federico Baserga
- Experimental Molecular Biophysics
- Freie Universität Berlin
- 14195 Berlin
- Germany
| | - Ernst-Walter Knapp
- Institute of Chemistry and Biochemistry
- Freie Universität Berlin
- 14195 Berlin
- Germany
| | - Sven T. Stripp
- Experimental Molecular Biophysics
- Freie Universität Berlin
- 14195 Berlin
- Germany
| | - Joachim Heberle
- Experimental Molecular Biophysics
- Freie Universität Berlin
- 14195 Berlin
- Germany
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Stripp ST, Lindenstrauss U, Sawers RG, Soboh B. Identification of an Isothiocyanate on the HypEF Complex Suggests a Route for Efficient Cyanyl-Group Channeling during [NiFe]-Hydrogenase Cofactor Generation. PLoS One 2015; 10:e0133118. [PMID: 26186649 PMCID: PMC4506123 DOI: 10.1371/journal.pone.0133118] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 06/24/2015] [Indexed: 01/12/2023] Open
Abstract
[NiFe]–hydrogenases catalyze uptake and evolution of H2 in a wide range of microorganisms. The enzyme is characterized by an inorganic nickel/ iron cofactor, the latter of which carries carbon monoxide and cyanide ligands. In vivo generation of these ligands requires a number of auxiliary proteins, the so–called Hyp family. Initially, HypF binds and activates the precursor metabolite carbamoyl phosphate. HypF catalyzes removal of phosphate and transfers the carbamate group to HypE. In an ATP–dependent condensation reaction, the C–terminal cysteinyl residue of HypE is modified to what has been interpreted as thiocyanate. This group is the direct precursor of the cyanide ligands of the [NiFe]–hydrogenase active site cofactor. We present a FT–IR analysis of HypE and HypF as isolated from E. coli. We follow the HypF–catalyzed cyanation of HypE in vitro and screen for the influence of carbamoyl phosphate and ATP. To elucidate on the differences between HypE and the HypEF complex, spectro–electrochemistry was used to map the vibrational Stark effect of naturally cyanated HypE. The IR signature of HypE could ultimately be assigned to isothiocyanate (–N=C=S) rather than thiocyanate (–S–C≡N). This has important implications for cyanyl–group channeling during [NiFe]–hydrogenase cofactor generation.
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Affiliation(s)
- Sven T. Stripp
- Department of Physics, Freie Universität Berlin, Berlin, Germany
- * E-mail:
| | - Ute Lindenstrauss
- Institute of Microbiology, Martin–Luther University Halle–Wittenberg, Halle (Saale), Germany
| | - R. Gary Sawers
- Institute of Microbiology, Martin–Luther University Halle–Wittenberg, Halle (Saale), Germany
| | - Basem Soboh
- Institute of Microbiology, Martin–Luther University Halle–Wittenberg, Halle (Saale), Germany
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Stripp ST, Lindenstrauss U, Granich C, Sawers RG, Soboh B. The influence of oxygen on [NiFe]-hydrogenase cofactor biosynthesis and how ligation of carbon monoxide precedes cyanation. PLoS One 2014; 9:e107488. [PMID: 25211029 PMCID: PMC4161419 DOI: 10.1371/journal.pone.0107488] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 08/13/2014] [Indexed: 01/14/2023] Open
Abstract
The class of [NiFe]–hydrogenases is characterized by a bimetallic cofactor comprising low–spin nickel and iron ions, the latter of which is modified with a single carbon monoxide (CO) and two cyanide (CN−) molecules. Generation of these ligands in vivo requires a complex maturation apparatus in which the HypC–HypD complex acts as a ‘construction site’ for the Fe–(CN)2CO portion of the cofactor. The order of addition of the CO and CN– ligands determines the ultimate structure and catalytic efficiency of the cofactor; however much debate surrounds the succession of events. Here, we present an FT–IR spectroscopic analysis of HypC–HypD isolated from a hydrogenase–competent wild–type strain of Escherichia coli. In contrast to previously reported samples, HypC–HypD showed spectral contributions indicative of an electron–rich Fe–CO cofactor, at the same time lacking any Fe–CN– signatures. This immature iron site binds external CO and undergoes oxidative damage when in contact with O2. Binding of CO protects the site against loss of spectral features associated with O2 damage. Our findings strongly suggest that CO ligation precedes cyanation in vivo. Furthermore, the results provide a rationale for the deleterious effects of O2 on in vivo cofactor biosynthesis.
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Affiliation(s)
- Sven T Stripp
- Department of Physics, Freie Universität Berlin, Berlin, Germany
| | - Ute Lindenstrauss
- Institute of Microbiology, Martin-Luther Universität Halle-Wittenberg, Halle (Saale), Germany
| | - Claudia Granich
- Institute of Microbiology, Martin-Luther Universität Halle-Wittenberg, Halle (Saale), Germany
| | - R Gary Sawers
- Institute of Microbiology, Martin-Luther Universität Halle-Wittenberg, Halle (Saale), Germany
| | - Basem Soboh
- Institute of Microbiology, Martin-Luther Universität Halle-Wittenberg, Halle (Saale), Germany
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Soboh B, Stripp ST, Bielak C, Lindenstrauß U, Braussemann M, Javaid M, Hallensleben M, Granich C, Herzberg M, Heberle J, Sawers RG. The [NiFe]-hydrogenase accessory chaperones HypC and HybG of Escherichia coli are iron- and carbon dioxide-binding proteins. FEBS Lett 2013; 587:2512-6. [PMID: 23851071 DOI: 10.1016/j.febslet.2013.06.055] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 06/27/2013] [Accepted: 06/27/2013] [Indexed: 12/26/2022]
Abstract
[NiFe]-hydrogenase accessory proteins HypC and HypD form a complex that binds a Fe-(CN)₂CO moiety and CO₂. In this study two HypC homologues from Escherichia coli were purified under strictly anaerobic conditions and both contained sub-stoichiometric amounts of iron (approx. 0.3 molFe/mol HypC). Infrared spectroscopic analysis identified a signature at 2337 cm⁻¹ indicating bound CO₂. Aerobically isolated HypC lacked both Fe and CO₂. Exchange of either of the highly conserved amino acid residues Cys2 or His51 abolished both Fe- and CO₂-binding. Our results suggest that HypC delivers CO₂ bound directly to Fe for reduction to CO by HypD.
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Affiliation(s)
- Basem Soboh
- Institute of Microbiology, Martin-Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle (Saale), Germany
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Stripp ST, Soboh B, Lindenstrauss U, Braussemann M, Herzberg M, Nies DH, Sawers RG, Heberle J. HypD is the scaffold protein for Fe-(CN)2CO cofactor assembly in [NiFe]-hydrogenase maturation. Biochemistry 2013; 52:3289-96. [PMID: 23597401 DOI: 10.1021/bi400302v] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[NiFe]-hydrogenases bind a NiFe-(CN)2CO cofactor in their catalytic large subunit. The iron-sulfur protein HypD and the small accessory protein HypC play a central role in the generation of the CO and CN(-) ligands. Infrared spectroscopy identified signatures on an anaerobically isolated HypCD complex that are reminiscent of those in the hydrogenase active site, suggesting that this complex is the assembly site of the Fe-(CN)2CO moiety of the cofactor prior to its transfer to the hydrogenase large subunit. Here, we report that HypD isolated in the absence of HypC shows infrared bands at 1956 cm(-1), 2072 cm(-1), and 2092 cm(-1) that can be assigned to CO, CN(1), and CN(2), respectively, and which are indistinguishable from those observed for the HypCD complex. HypC could not be isolated with CO or CN(-) ligand contribution. Treatment of HypD with EDTA led to the concomitant loss of Fe and the CO and CN(-) signatures, while oxidation by H2O2 resulted in a positive shift of the CO and CN(-) bands by 35 cm(-1) and 20 cm(-1), respectively, indicative of the ferrous iron as an immediate ligation site for the diatomic ligands. Analysis of HypD amino acid variants identified cysteines 41, 69, and 72 to be essential for maturation of the cofactor. We propose a refined model for the ligation of Fe-(CN)2CO to HypD and the role of HypC in [NiFe]-hydrogenase maturation.
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Affiliation(s)
- Sven T Stripp
- Experimental Molecular Biophysics, Freie Universität Berlin , Arnimalle 14, 14195 Berlin, Germany
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Soboh B, Stripp ST, Muhr E, Granich C, Braussemann M, Herzberg M, Heberle J, Gary Sawers R. [NiFe]-hydrogenase maturation: Isolation of a HypC-HypD complex carrying diatomic CO and CN−
ligands. FEBS Lett 2012; 586:3882-7. [DOI: 10.1016/j.febslet.2012.09.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 09/12/2012] [Accepted: 09/13/2012] [Indexed: 10/27/2022]
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Krassen H, Stripp ST, Böhm N, Berkessel A, Happe T, Ataka K, Heberle J. Tailor-Made Modification of a Gold Surface for the Chemical Binding of a High-Activity [FeFe] Hydrogenase. Eur J Inorg Chem 2011. [DOI: 10.1002/ejic.201001190] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Wait AF, Brandmayr C, Stripp ST, Cavazza C, Fontecilla-Camps JC, Happe T, Armstrong FA. Formaldehyde—A Rapid and Reversible Inhibitor of Hydrogen Production by [FeFe]-Hydrogenases. J Am Chem Soc 2011; 133:1282-5. [DOI: 10.1021/ja110103p] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Annemarie F. Wait
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Caterina Brandmayr
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
| | - Sven T. Stripp
- Lehrstuhl fur Biochemie der Pflanzen, AG Photobiotechnologie, Ruhr-Universität, 44780 Bochum, Germany
| | - Christine Cavazza
- Laboratoire de Crystallographie et Crystallographie des Protéines, Institut de Biologie Structurale, J.P. Ebel, CEA, CNRS, Université Joseph Fourier, 41, rue J. Horowitz, 38027 Grenoble Cedex 1, France
| | - Juan C. Fontecilla-Camps
- Laboratoire de Crystallographie et Crystallographie des Protéines, Institut de Biologie Structurale, J.P. Ebel, CEA, CNRS, Université Joseph Fourier, 41, rue J. Horowitz, 38027 Grenoble Cedex 1, France
| | - Thomas Happe
- Lehrstuhl fur Biochemie der Pflanzen, AG Photobiotechnologie, Ruhr-Universität, 44780 Bochum, Germany
| | - Fraser A. Armstrong
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K
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Goldet G, Brandmayr C, Stripp ST, Happe T, Cavazza C, Fontecilla-Camps JC, Armstrong FA. Electrochemical kinetic investigations of the reactions of [FeFe]-hydrogenases with carbon monoxide and oxygen: comparing the importance of gas tunnels and active-site electronic/redox effects. J Am Chem Soc 2010; 131:14979-89. [PMID: 19824734 DOI: 10.1021/ja905388j] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A major obstacle for future biohydrogen production is the oxygen sensitivity of [FeFe]-hydrogenases, the highly active catalysts produced by bacteria and green algae. The reactions of three representative [FeFe]-hydrogenases with O(2) have been studied by protein film electrochemistry under conditions of both H(2) oxidation and H(2) production, using CO as a complementary probe. The hydrogenases are DdHydAB and CaHydA from the bacteria Desulfovibrio desulfuricans and Clostridium acetobutylicum , and CrHydA1 from the green alga Chlamydomonas reinhardtii . Rates of inactivation depend on the redox state of the active site 'H-cluster' and on transport through the protein to reach the pocket in which the H-cluster is housed. In all cases CO reacts much faster than O(2). In the model proposed, CaHydA shows the most sluggish gas transport and hence little dependence of inactivation rate on H-cluster state, whereas DdHydAB shows a large dependence on H-cluster state and the least effective barrier to gas transport. All three enzymes show a similar rate of reactivation from CO inhibition, which increases upon illumination: the rate-determining step is thus assigned to cleavage of the labile Fe-CO bond, a reaction likely to be intrinsic to the atomic and electronic state of the H-cluster and less sensitive to the surrounding protein.
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Affiliation(s)
- Gabrielle Goldet
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
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Stripp ST, Goldet G, Brandmayr C, Sanganas O, Vincent KA, Haumann M, Armstrong FA, Happe T. How oxygen attacks [FeFe] hydrogenases from photosynthetic organisms. Proc Natl Acad Sci U S A 2009; 106:17331-6. [PMID: 19805068 PMCID: PMC2765078 DOI: 10.1073/pnas.0905343106] [Citation(s) in RCA: 214] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Indexed: 12/31/2022] Open
Abstract
Green algae such as Chlamydomonas reinhardtii synthesize an [FeFe] hydrogenase that is highly active in hydrogen evolution. However, the extreme sensitivity of [FeFe] hydrogenases to oxygen presents a major challenge for exploiting these organisms to achieve sustainable photosynthetic hydrogen production. In this study, the mechanism of oxygen inactivation of the [FeFe] hydrogenase CrHydA1 from C. reinhardtii has been investigated. X-ray absorption spectroscopy shows that reaction with oxygen results in destruction of the [4Fe-4S] domain of the active site H-cluster while leaving the di-iron domain (2Fe(H)) essentially intact. By protein film electrochemistry we were able to determine the order of events leading up to this destruction. Carbon monoxide, a competitive inhibitor of CrHydA1 which binds to an Fe atom of the 2Fe(H) domain and is otherwise not known to attack FeS clusters in proteins, reacts nearly two orders of magnitude faster than oxygen and protects the enzyme against oxygen damage. These results therefore show that destruction of the [4Fe-4S] cluster is initiated by binding and reduction of oxygen at the di-iron domain-a key step that is blocked by carbon monoxide. The relatively slow attack by oxygen compared to carbon monoxide suggests that a very high level of discrimination can be achieved by subtle factors such as electronic effects (specific orbital overlap requirements) and steric constraints at the active site.
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Affiliation(s)
- Sven T. Stripp
- Lehrstuhl Biochemie der Pflanzen, AG Photobiotechnologie, Ruhr Universität Bochum, Universitätsstrasse 150, 44801 Bochum, Germany
| | - Gabrielle Goldet
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom; and
| | - Caterina Brandmayr
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom; and
| | - Oliver Sanganas
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Kylie A. Vincent
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom; and
| | - Michael Haumann
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Fraser A. Armstrong
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom; and
| | - Thomas Happe
- Lehrstuhl Biochemie der Pflanzen, AG Photobiotechnologie, Ruhr Universität Bochum, Universitätsstrasse 150, 44801 Bochum, Germany
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